1 /* ---------------------------------------------------------------------------
2 * $Id: Schedule.c,v 1.50 2000/03/13 09:57:16 simonmar Exp $
4 * (c) The GHC Team, 1998-2000
8 * The main scheduling code in GranSim is quite different from that in std
9 * (concurrent) Haskell: while concurrent Haskell just iterates over the
10 * threads in the runnable queue, GranSim is event driven, i.e. it iterates
11 * over the events in the global event queue. -- HWL
12 * --------------------------------------------------------------------------*/
14 //@node Main scheduling code, , ,
15 //@section Main scheduling code
17 /* Version with scheduler monitor support for SMPs.
19 This design provides a high-level API to create and schedule threads etc.
20 as documented in the SMP design document.
22 It uses a monitor design controlled by a single mutex to exercise control
23 over accesses to shared data structures, and builds on the Posix threads
26 The majority of state is shared. In order to keep essential per-task state,
27 there is a Capability structure, which contains all the information
28 needed to run a thread: its STG registers, a pointer to its TSO, a
29 nursery etc. During STG execution, a pointer to the capability is
30 kept in a register (BaseReg).
32 In a non-SMP build, there is one global capability, namely MainRegTable.
39 //* Variables and Data structures::
41 //* Main scheduling loop::
42 //* Suspend and Resume::
44 //* Garbage Collextion Routines::
45 //* Blocking Queue Routines::
46 //* Exception Handling Routines::
47 //* Debugging Routines::
51 //@node Includes, Variables and Data structures, Main scheduling code, Main scheduling code
52 //@subsection Includes
60 #include "StgStartup.h"
64 #include "StgMiscClosures.h"
66 #include "Evaluator.h"
67 #include "Exception.h"
71 #include "Profiling.h"
75 #if defined(GRAN) || defined(PAR)
76 # include "GranSimRts.h"
78 # include "ParallelRts.h"
79 # include "Parallel.h"
80 # include "ParallelDebug.h"
87 //@node Variables and Data structures, Prototypes, Includes, Main scheduling code
88 //@subsection Variables and Data structures
92 * These are the threads which clients have requested that we run.
94 * In an SMP build, we might have several concurrent clients all
95 * waiting for results, and each one will wait on a condition variable
96 * until the result is available.
98 * In non-SMP, clients are strictly nested: the first client calls
99 * into the RTS, which might call out again to C with a _ccall_GC, and
100 * eventually re-enter the RTS.
102 * Main threads information is kept in a linked list:
104 //@cindex StgMainThread
105 typedef struct StgMainThread_ {
107 SchedulerStatus stat;
110 pthread_cond_t wakeup;
112 struct StgMainThread_ *link;
115 /* Main thread queue.
116 * Locks required: sched_mutex.
118 static StgMainThread *main_threads;
121 * Locks required: sched_mutex.
126 StgTSO* ActiveTSO = NULL; /* for assigning system costs; GranSim-Light only */
127 /* rtsTime TimeOfNextEvent, EndOfTimeSlice; now in GranSim.c */
130 In GranSim we have a runable and a blocked queue for each processor.
131 In order to minimise code changes new arrays run_queue_hds/tls
132 are created. run_queue_hd is then a short cut (macro) for
133 run_queue_hds[CurrentProc] (see GranSim.h).
136 StgTSO *run_queue_hds[MAX_PROC], *run_queue_tls[MAX_PROC];
137 StgTSO *blocked_queue_hds[MAX_PROC], *blocked_queue_tls[MAX_PROC];
138 StgTSO *ccalling_threadss[MAX_PROC];
142 //@cindex run_queue_hd
143 //@cindex run_queue_tl
144 //@cindex blocked_queue_hd
145 //@cindex blocked_queue_tl
146 StgTSO *run_queue_hd, *run_queue_tl;
147 StgTSO *blocked_queue_hd, *blocked_queue_tl;
149 /* Threads suspended in _ccall_GC.
150 * Locks required: sched_mutex.
152 static StgTSO *suspended_ccalling_threads;
154 static void GetRoots(void);
155 static StgTSO *threadStackOverflow(StgTSO *tso);
158 /* KH: The following two flags are shared memory locations. There is no need
159 to lock them, since they are only unset at the end of a scheduler
163 /* flag set by signal handler to precipitate a context switch */
164 //@cindex context_switch
167 /* if this flag is set as well, give up execution */
168 //@cindex interrupted
171 /* Next thread ID to allocate.
172 * Locks required: sched_mutex
174 //@cindex next_thread_id
175 StgThreadID next_thread_id = 1;
178 * Pointers to the state of the current thread.
179 * Rule of thumb: if CurrentTSO != NULL, then we're running a Haskell
180 * thread. If CurrentTSO == NULL, then we're at the scheduler level.
183 /* The smallest stack size that makes any sense is:
184 * RESERVED_STACK_WORDS (so we can get back from the stack overflow)
185 * + sizeofW(StgStopFrame) (the stg_stop_thread_info frame)
186 * + 1 (the realworld token for an IO thread)
187 * + 1 (the closure to enter)
189 * A thread with this stack will bomb immediately with a stack
190 * overflow, which will increase its stack size.
193 #define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 2)
195 /* Free capability list.
196 * Locks required: sched_mutex.
199 //@cindex free_capabilities
200 //@cindex n_free_capabilities
201 Capability *free_capabilities; /* Available capabilities for running threads */
202 nat n_free_capabilities; /* total number of available capabilities */
204 //@cindex MainRegTable
205 Capability MainRegTable; /* for non-SMP, we have one global capability */
209 StgTSO *CurrentTSOs[MAX_PROC];
216 /* All our current task ids, saved in case we need to kill them later.
223 void addToBlockedQueue ( StgTSO *tso );
225 static void schedule ( void );
226 void interruptStgRts ( void );
227 static StgTSO * createThread_ ( nat size, rtsBool have_lock );
230 static void sched_belch(char *s, ...);
234 //@cindex sched_mutex
236 //@cindex thread_ready_cond
237 //@cindex gc_pending_cond
238 pthread_mutex_t sched_mutex = PTHREAD_MUTEX_INITIALIZER;
239 pthread_mutex_t term_mutex = PTHREAD_MUTEX_INITIALIZER;
240 pthread_cond_t thread_ready_cond = PTHREAD_COND_INITIALIZER;
241 pthread_cond_t gc_pending_cond = PTHREAD_COND_INITIALIZER;
248 rtsTime TimeOfLastYield;
252 * The thread state for the main thread.
253 // ToDo: check whether not needed any more
258 //@node Prototypes, Main scheduling loop, Variables and Data structures, Main scheduling code
259 //@subsection Prototypes
261 //@node Main scheduling loop, Suspend and Resume, Prototypes, Main scheduling code
262 //@subsection Main scheduling loop
264 /* ---------------------------------------------------------------------------
265 Main scheduling loop.
267 We use round-robin scheduling, each thread returning to the
268 scheduler loop when one of these conditions is detected:
271 * timer expires (thread yields)
276 Locking notes: we acquire the scheduler lock once at the beginning
277 of the scheduler loop, and release it when
279 * running a thread, or
280 * waiting for work, or
281 * waiting for a GC to complete.
283 ------------------------------------------------------------------------ */
290 StgThreadReturnCode ret;
298 rtsBool was_interrupted = rtsFalse;
300 ACQUIRE_LOCK(&sched_mutex);
303 # error ToDo: implement GranSim scheduler
305 while (!GlobalStopPending) { /* GlobalStopPending set in par_exit */
307 if (PendingFetches != END_BF_QUEUE) {
314 /* If we're interrupted (the user pressed ^C, or some other
315 * termination condition occurred), kill all the currently running
319 IF_DEBUG(scheduler, sched_belch("interrupted"));
320 for (t = run_queue_hd; t != END_TSO_QUEUE; t = t->link) {
323 for (t = blocked_queue_hd; t != END_TSO_QUEUE; t = t->link) {
326 run_queue_hd = run_queue_tl = END_TSO_QUEUE;
327 blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
328 interrupted = rtsFalse;
329 was_interrupted = rtsTrue;
332 /* Go through the list of main threads and wake up any
333 * clients whose computations have finished. ToDo: this
334 * should be done more efficiently without a linear scan
335 * of the main threads list, somehow...
339 StgMainThread *m, **prev;
340 prev = &main_threads;
341 for (m = main_threads; m != NULL; m = m->link) {
342 switch (m->tso->whatNext) {
345 *(m->ret) = (StgClosure *)m->tso->sp[0];
349 pthread_cond_broadcast(&m->wakeup);
353 if (was_interrupted) {
354 m->stat = Interrupted;
358 pthread_cond_broadcast(&m->wakeup);
366 /* If our main thread has finished or been killed, return.
369 StgMainThread *m = main_threads;
370 if (m->tso->whatNext == ThreadComplete
371 || m->tso->whatNext == ThreadKilled) {
372 main_threads = main_threads->link;
373 if (m->tso->whatNext == ThreadComplete) {
374 /* we finished successfully, fill in the return value */
375 if (m->ret) { *(m->ret) = (StgClosure *)m->tso->sp[0]; };
379 if (was_interrupted) {
380 m->stat = Interrupted;
390 /* Top up the run queue from our spark pool. We try to make the
391 * number of threads in the run queue equal to the number of
396 nat n = n_free_capabilities;
397 StgTSO *tso = run_queue_hd;
399 /* Count the run queue */
400 while (n > 0 && tso != END_TSO_QUEUE) {
409 break; /* no more sparks in the pool */
411 /* I'd prefer this to be done in activateSpark -- HWL */
412 /* tricky - it needs to hold the scheduler lock and
413 * not try to re-acquire it -- SDM */
415 tso = createThread_(RtsFlags.GcFlags.initialStkSize, rtsTrue);
416 pushClosure(tso,spark);
417 PUSH_ON_RUN_QUEUE(tso);
419 advisory_thread_count++;
423 sched_belch("turning spark of closure %p into a thread",
424 (StgClosure *)spark));
427 /* We need to wake up the other tasks if we just created some
430 if (n_free_capabilities - n > 1) {
431 pthread_cond_signal(&thread_ready_cond);
436 /* Check whether any waiting threads need to be woken up. If the
437 * run queue is empty, and there are no other tasks running, we
438 * can wait indefinitely for something to happen.
439 * ToDo: what if another client comes along & requests another
442 if (blocked_queue_hd != END_TSO_QUEUE) {
444 (run_queue_hd == END_TSO_QUEUE)
446 && (n_free_capabilities == RtsFlags.ParFlags.nNodes)
451 /* check for signals each time around the scheduler */
453 if (signals_pending()) {
454 start_signal_handlers();
458 /* Detect deadlock: when we have no threads to run, there are
459 * no threads waiting on I/O or sleeping, and all the other
460 * tasks are waiting for work, we must have a deadlock. Inform
461 * all the main threads.
464 if (blocked_queue_hd == END_TSO_QUEUE
465 && run_queue_hd == END_TSO_QUEUE
466 && (n_free_capabilities == RtsFlags.ParFlags.nNodes)
469 for (m = main_threads; m != NULL; m = m->link) {
472 pthread_cond_broadcast(&m->wakeup);
477 if (blocked_queue_hd == END_TSO_QUEUE
478 && run_queue_hd == END_TSO_QUEUE) {
479 StgMainThread *m = main_threads;
482 main_threads = m->link;
488 /* If there's a GC pending, don't do anything until it has
492 IF_DEBUG(scheduler,sched_belch("waiting for GC"));
493 pthread_cond_wait(&gc_pending_cond, &sched_mutex);
496 /* block until we've got a thread on the run queue and a free
499 while (run_queue_hd == END_TSO_QUEUE || free_capabilities == NULL) {
500 IF_DEBUG(scheduler, sched_belch("waiting for work"));
501 pthread_cond_wait(&thread_ready_cond, &sched_mutex);
502 IF_DEBUG(scheduler, sched_belch("work now available"));
507 # error ToDo: implement GranSim scheduler
509 /* ToDo: phps merge with spark activation above */
510 /* check whether we have local work and send requests if we have none */
511 if (run_queue_hd == END_TSO_QUEUE) { /* no runnable threads */
512 /* :-[ no local threads => look out for local sparks */
513 if (advisory_thread_count < RtsFlags.ParFlags.maxThreads &&
514 (pending_sparks_hd[REQUIRED_POOL] < pending_sparks_tl[REQUIRED_POOL] ||
515 pending_sparks_hd[ADVISORY_POOL] < pending_sparks_tl[ADVISORY_POOL])) {
517 * ToDo: add GC code check that we really have enough heap afterwards!!
519 * If we're here (no runnable threads) and we have pending
520 * sparks, we must have a space problem. Get enough space
521 * to turn one of those pending sparks into a
525 spark = findSpark(); /* get a spark */
526 if (spark != (rtsSpark) NULL) {
527 tso = activateSpark(spark); /* turn the spark into a thread */
528 IF_PAR_DEBUG(verbose,
529 belch("== [%x] schedule: Created TSO %p (%d); %d threads active",
530 mytid, tso, tso->id, advisory_thread_count));
532 if (tso==END_TSO_QUEUE) { /* failed to activate spark->back to loop */
533 belch("^^ failed to activate spark");
535 } /* otherwise fall through & pick-up new tso */
537 IF_PAR_DEBUG(verbose,
538 belch("^^ no local sparks (spark pool contains only NFs: %d)",
539 spark_queue_len(ADVISORY_POOL)));
543 /* =8-[ no local sparks => look for work on other PEs */
546 * We really have absolutely no work. Send out a fish
547 * (there may be some out there already), and wait for
548 * something to arrive. We clearly can't run any threads
549 * until a SCHEDULE or RESUME arrives, and so that's what
550 * we're hoping to see. (Of course, we still have to
551 * respond to other types of messages.)
554 outstandingFishes < RtsFlags.ParFlags.maxFishes ) { // &&
555 // (last_fish_arrived_at+FISH_DELAY < CURRENT_TIME)) {
556 /* fishing set in sendFish, processFish;
557 avoid flooding system with fishes via delay */
559 sendFish(pe, mytid, NEW_FISH_AGE, NEW_FISH_HISTORY,
567 } else if (PacketsWaiting()) { /* Look for incoming messages */
571 /* Now we are sure that we have some work available */
572 ASSERT(run_queue_hd != END_TSO_QUEUE);
573 /* Take a thread from the run queue, if we have work */
574 t = take_off_run_queue(END_TSO_QUEUE);
576 /* ToDo: write something to the log-file
577 if (RTSflags.ParFlags.granSimStats && !sameThread)
578 DumpGranEvent(GR_SCHEDULE, RunnableThreadsHd);
583 IF_DEBUG(scheduler, belch("--^^ %d sparks on [%#x] (hd=%x; tl=%x; lim=%x)",
584 spark_queue_len(ADVISORY_POOL), CURRENT_PROC,
585 pending_sparks_hd[ADVISORY_POOL],
586 pending_sparks_tl[ADVISORY_POOL],
587 pending_sparks_lim[ADVISORY_POOL]));
589 IF_DEBUG(scheduler, belch("--== %d threads on [%#x] (hd=%x; tl=%x)",
590 run_queue_len(), CURRENT_PROC,
591 run_queue_hd, run_queue_tl));
595 we are running a different TSO, so write a schedule event to log file
596 NB: If we use fair scheduling we also have to write a deschedule
597 event for LastTSO; with unfair scheduling we know that the
598 previous tso has blocked whenever we switch to another tso, so
599 we don't need it in GUM for now
601 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
602 GR_SCHEDULE, t, (StgClosure *)NULL, 0, 0);
606 #else /* !GRAN && !PAR */
608 /* grab a thread from the run queue
611 IF_DEBUG(sanity,checkTSO(t));
618 cap = free_capabilities;
619 free_capabilities = cap->link;
620 n_free_capabilities--;
625 cap->rCurrentTSO = t;
627 /* set the context_switch flag
629 if (run_queue_hd == END_TSO_QUEUE)
634 RELEASE_LOCK(&sched_mutex);
636 IF_DEBUG(scheduler,sched_belch("running thread %d", t->id));
638 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
639 /* Run the current thread
641 switch (cap->rCurrentTSO->whatNext) {
644 /* Thread already finished, return to scheduler. */
645 ret = ThreadFinished;
648 ret = StgRun((StgFunPtr) stg_enterStackTop, cap);
651 ret = StgRun((StgFunPtr) stg_returnToStackTop, cap);
653 case ThreadEnterHugs:
657 IF_DEBUG(scheduler,sched_belch("entering Hugs"));
658 c = (StgClosure *)(cap->rCurrentTSO->sp[0]);
659 cap->rCurrentTSO->sp += 1;
664 barf("Panic: entered a BCO but no bytecode interpreter in this build");
667 barf("schedule: invalid whatNext field");
669 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
671 /* Costs for the scheduler are assigned to CCS_SYSTEM */
676 ACQUIRE_LOCK(&sched_mutex);
679 IF_DEBUG(scheduler,fprintf(stderr,"scheduler (task %ld): ", pthread_self()););
681 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: "););
683 t = cap->rCurrentTSO;
687 /* make all the running tasks block on a condition variable,
688 * maybe set context_switch and wait till they all pile in,
689 * then have them wait on a GC condition variable.
691 IF_DEBUG(scheduler,belch("thread %ld stopped: HeapOverflow", t->id));
694 ready_to_gc = rtsTrue;
695 context_switch = 1; /* stop other threads ASAP */
696 PUSH_ON_RUN_QUEUE(t);
700 /* just adjust the stack for this thread, then pop it back
703 IF_DEBUG(scheduler,belch("thread %ld stopped, StackOverflow", t->id));
707 /* enlarge the stack */
708 StgTSO *new_t = threadStackOverflow(t);
710 /* This TSO has moved, so update any pointers to it from the
711 * main thread stack. It better not be on any other queues...
714 for (m = main_threads; m != NULL; m = m->link) {
720 PUSH_ON_RUN_QUEUE(new_t);
727 DumpGranEvent(GR_DESCHEDULE, t));
728 globalGranStats.tot_yields++;
731 DumpGranEvent(GR_DESCHEDULE, t));
733 /* put the thread back on the run queue. Then, if we're ready to
734 * GC, check whether this is the last task to stop. If so, wake
735 * up the GC thread. getThread will block during a GC until the
739 if (t->whatNext == ThreadEnterHugs) {
740 /* ToDo: or maybe a timer expired when we were in Hugs?
741 * or maybe someone hit ctrl-C
743 belch("thread %ld stopped to switch to Hugs", t->id);
745 belch("thread %ld stopped, yielding", t->id);
749 APPEND_TO_RUN_QUEUE(t);
754 # error ToDo: implement GranSim scheduler
757 DumpGranEvent(GR_DESCHEDULE, t));
760 /* don't need to do anything. Either the thread is blocked on
761 * I/O, in which case we'll have called addToBlockedQueue
762 * previously, or it's blocked on an MVar or Blackhole, in which
763 * case it'll be on the relevant queue already.
766 fprintf(stderr, "thread %d stopped, ", t->id);
767 printThreadBlockage(t);
768 fprintf(stderr, "\n"));
773 /* Need to check whether this was a main thread, and if so, signal
774 * the task that started it with the return value. If we have no
775 * more main threads, we probably need to stop all the tasks until
778 IF_DEBUG(scheduler,belch("thread %ld finished", t->id));
779 t->whatNext = ThreadComplete;
781 // ToDo: endThread(t, CurrentProc); // clean-up the thread
783 advisory_thread_count--;
784 if (RtsFlags.ParFlags.ParStats.Full)
785 DumpEndEvent(CURRENT_PROC, t, rtsFalse /* not mandatory */);
790 barf("doneThread: invalid thread return code");
794 cap->link = free_capabilities;
795 free_capabilities = cap;
796 n_free_capabilities++;
800 if (ready_to_gc && n_free_capabilities == RtsFlags.ParFlags.nNodes)
805 /* everybody back, start the GC.
806 * Could do it in this thread, or signal a condition var
807 * to do it in another thread. Either way, we need to
808 * broadcast on gc_pending_cond afterward.
811 IF_DEBUG(scheduler,sched_belch("doing GC"));
813 GarbageCollect(GetRoots);
814 ready_to_gc = rtsFalse;
816 pthread_cond_broadcast(&gc_pending_cond);
821 IF_GRAN_DEBUG(unused,
822 print_eventq(EventHd));
824 event = get_next_event();
828 /* ToDo: wait for next message to arrive rather than busy wait */
833 t = take_off_run_queue(END_TSO_QUEUE);
836 } /* end of while(1) */
839 /* A hack for Hugs concurrency support. Needs sanitisation (?) */
840 void deleteAllThreads ( void )
843 IF_DEBUG(scheduler,sched_belch("deleteAllThreads()"));
844 for (t = run_queue_hd; t != END_TSO_QUEUE; t = t->link) {
847 for (t = blocked_queue_hd; t != END_TSO_QUEUE; t = t->link) {
850 run_queue_hd = run_queue_tl = END_TSO_QUEUE;
851 blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
854 /* startThread and insertThread are now in GranSim.c -- HWL */
856 //@node Suspend and Resume, Run queue code, Main scheduling loop, Main scheduling code
857 //@subsection Suspend and Resume
859 /* ---------------------------------------------------------------------------
860 * Suspending & resuming Haskell threads.
862 * When making a "safe" call to C (aka _ccall_GC), the task gives back
863 * its capability before calling the C function. This allows another
864 * task to pick up the capability and carry on running Haskell
865 * threads. It also means that if the C call blocks, it won't lock
868 * The Haskell thread making the C call is put to sleep for the
869 * duration of the call, on the susepended_ccalling_threads queue. We
870 * give out a token to the task, which it can use to resume the thread
871 * on return from the C function.
872 * ------------------------------------------------------------------------- */
875 suspendThread( Capability *cap )
879 ACQUIRE_LOCK(&sched_mutex);
882 sched_belch("thread %d did a _ccall_gc\n", cap->rCurrentTSO->id));
884 threadPaused(cap->rCurrentTSO);
885 cap->rCurrentTSO->link = suspended_ccalling_threads;
886 suspended_ccalling_threads = cap->rCurrentTSO;
888 /* Use the thread ID as the token; it should be unique */
889 tok = cap->rCurrentTSO->id;
892 cap->link = free_capabilities;
893 free_capabilities = cap;
894 n_free_capabilities++;
897 RELEASE_LOCK(&sched_mutex);
902 resumeThread( StgInt tok )
907 ACQUIRE_LOCK(&sched_mutex);
909 prev = &suspended_ccalling_threads;
910 for (tso = suspended_ccalling_threads;
911 tso != END_TSO_QUEUE;
912 prev = &tso->link, tso = tso->link) {
913 if (tso->id == (StgThreadID)tok) {
918 if (tso == END_TSO_QUEUE) {
919 barf("resumeThread: thread not found");
923 while (free_capabilities == NULL) {
924 IF_DEBUG(scheduler, sched_belch("waiting to resume"));
925 pthread_cond_wait(&thread_ready_cond, &sched_mutex);
926 IF_DEBUG(scheduler, sched_belch("resuming thread %d", tso->id));
928 cap = free_capabilities;
929 free_capabilities = cap->link;
930 n_free_capabilities--;
935 cap->rCurrentTSO = tso;
937 RELEASE_LOCK(&sched_mutex);
942 /* ---------------------------------------------------------------------------
944 * ------------------------------------------------------------------------ */
945 static void unblockThread(StgTSO *tso);
947 /* ---------------------------------------------------------------------------
948 * Comparing Thread ids.
950 * This is used from STG land in the implementation of the
951 * instances of Eq/Ord for ThreadIds.
952 * ------------------------------------------------------------------------ */
954 int cmp_thread(const StgTSO *tso1, const StgTSO *tso2)
956 StgThreadID id1 = tso1->id;
957 StgThreadID id2 = tso2->id;
959 if (id1 < id2) return (-1);
960 if (id1 > id2) return 1;
964 /* ---------------------------------------------------------------------------
967 The new thread starts with the given stack size. Before the
968 scheduler can run, however, this thread needs to have a closure
969 (and possibly some arguments) pushed on its stack. See
970 pushClosure() in Schedule.h.
972 createGenThread() and createIOThread() (in SchedAPI.h) are
973 convenient packaged versions of this function.
974 ------------------------------------------------------------------------ */
975 //@cindex createThread
977 /* currently pri (priority) is only used in a GRAN setup -- HWL */
979 createThread(nat stack_size, StgInt pri)
981 return createThread_(stack_size, rtsFalse, pri);
985 createThread_(nat size, rtsBool have_lock, StgInt pri)
989 createThread(nat stack_size)
991 return createThread_(stack_size, rtsFalse);
995 createThread_(nat size, rtsBool have_lock)
1001 /* First check whether we should create a thread at all */
1003 /* check that no more than RtsFlags.ParFlags.maxThreads threads are created */
1004 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads) {
1006 belch("{createThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
1007 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
1008 return END_TSO_QUEUE;
1014 ASSERT(!RtsFlags.GranFlags.Light || CurrentProc==0);
1017 // ToDo: check whether size = stack_size - TSO_STRUCT_SIZEW
1019 /* catch ridiculously small stack sizes */
1020 if (size < MIN_STACK_WORDS + TSO_STRUCT_SIZEW) {
1021 size = MIN_STACK_WORDS + TSO_STRUCT_SIZEW;
1024 tso = (StgTSO *)allocate(size);
1025 TICK_ALLOC_TSO(size-sizeofW(StgTSO),0);
1027 stack_size = size - TSO_STRUCT_SIZEW;
1029 // Hmm, this CCS_MAIN is not protected by a PROFILING cpp var;
1030 SET_HDR(tso, &TSO_info, CCS_MAIN);
1032 SET_GRAN_HDR(tso, ThisPE);
1034 tso->whatNext = ThreadEnterGHC;
1036 /* tso->id needs to be unique. For now we use a heavyweight mutex to
1037 protect the increment operation on next_thread_id.
1038 In future, we could use an atomic increment instead.
1041 if (!have_lock) { ACQUIRE_LOCK(&sched_mutex); }
1042 tso->id = next_thread_id++;
1043 if (!have_lock) { RELEASE_LOCK(&sched_mutex); }
1045 tso->why_blocked = NotBlocked;
1046 tso->blocked_exceptions = NULL;
1048 tso->splim = (P_)&(tso->stack) + RESERVED_STACK_WORDS;
1049 tso->stack_size = stack_size;
1050 tso->max_stack_size = round_to_mblocks(RtsFlags.GcFlags.maxStkSize)
1052 tso->sp = (P_)&(tso->stack) + stack_size;
1055 tso->prof.CCCS = CCS_MAIN;
1058 /* put a stop frame on the stack */
1059 tso->sp -= sizeofW(StgStopFrame);
1060 SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_MAIN);
1061 tso->su = (StgUpdateFrame*)tso->sp;
1063 IF_DEBUG(scheduler,belch("---- Initialised TSO %ld (%p), stack size = %lx words",
1064 tso->id, tso, tso->stack_size));
1068 tso->link = END_TSO_QUEUE;
1069 /* uses more flexible routine in GranSim */
1070 insertThread(tso, CurrentProc);
1072 /* In a non-GranSim setup the pushing of a TSO onto the runq is separated
1078 tso->gran.pri = pri;
1079 tso->gran.magic = TSO_MAGIC; // debugging only
1080 tso->gran.sparkname = 0;
1081 tso->gran.startedat = CURRENT_TIME;
1082 tso->gran.exported = 0;
1083 tso->gran.basicblocks = 0;
1084 tso->gran.allocs = 0;
1085 tso->gran.exectime = 0;
1086 tso->gran.fetchtime = 0;
1087 tso->gran.fetchcount = 0;
1088 tso->gran.blocktime = 0;
1089 tso->gran.blockcount = 0;
1090 tso->gran.blockedat = 0;
1091 tso->gran.globalsparks = 0;
1092 tso->gran.localsparks = 0;
1093 if (RtsFlags.GranFlags.Light)
1094 tso->gran.clock = Now; /* local clock */
1096 tso->gran.clock = 0;
1098 IF_DEBUG(gran,printTSO(tso));
1100 tso->par.sparkname = 0;
1101 tso->par.startedat = CURRENT_TIME;
1102 tso->par.exported = 0;
1103 tso->par.basicblocks = 0;
1104 tso->par.allocs = 0;
1105 tso->par.exectime = 0;
1106 tso->par.fetchtime = 0;
1107 tso->par.fetchcount = 0;
1108 tso->par.blocktime = 0;
1109 tso->par.blockcount = 0;
1110 tso->par.blockedat = 0;
1111 tso->par.globalsparks = 0;
1112 tso->par.localsparks = 0;
1116 globalGranStats.tot_threads_created++;
1117 globalGranStats.threads_created_on_PE[CurrentProc]++;
1118 globalGranStats.tot_sq_len += spark_queue_len(CurrentProc);
1119 globalGranStats.tot_sq_probes++;
1122 IF_DEBUG(scheduler,sched_belch("created thread %ld, stack size = %lx words",
1123 tso->id, tso->stack_size));
1127 /* ---------------------------------------------------------------------------
1130 * scheduleThread puts a thread on the head of the runnable queue.
1131 * This will usually be done immediately after a thread is created.
1132 * The caller of scheduleThread must create the thread using e.g.
1133 * createThread and push an appropriate closure
1134 * on this thread's stack before the scheduler is invoked.
1135 * ------------------------------------------------------------------------ */
1138 scheduleThread(StgTSO *tso)
1140 ACQUIRE_LOCK(&sched_mutex);
1142 /* Put the new thread on the head of the runnable queue. The caller
1143 * better push an appropriate closure on this thread's stack
1144 * beforehand. In the SMP case, the thread may start running as
1145 * soon as we release the scheduler lock below.
1147 PUSH_ON_RUN_QUEUE(tso);
1150 IF_DEBUG(scheduler,printTSO(tso));
1151 RELEASE_LOCK(&sched_mutex);
1154 /* ---------------------------------------------------------------------------
1157 * Start up Posix threads to run each of the scheduler tasks.
1158 * I believe the task ids are not needed in the system as defined.
1160 * ------------------------------------------------------------------------ */
1164 taskStart( void *arg STG_UNUSED )
1171 /* ---------------------------------------------------------------------------
1174 * Initialise the scheduler. This resets all the queues - if the
1175 * queues contained any threads, they'll be garbage collected at the
1178 * This now calls startTasks(), so should only be called once! KH @ 25/10/99
1179 * ------------------------------------------------------------------------ */
1183 term_handler(int sig STG_UNUSED)
1186 ACQUIRE_LOCK(&term_mutex);
1188 RELEASE_LOCK(&term_mutex);
1193 //@cindex initScheduler
1200 for (i=0; i<=MAX_PROC; i++) {
1201 run_queue_hds[i] = END_TSO_QUEUE;
1202 run_queue_tls[i] = END_TSO_QUEUE;
1203 blocked_queue_hds[i] = END_TSO_QUEUE;
1204 blocked_queue_tls[i] = END_TSO_QUEUE;
1205 ccalling_threadss[i] = END_TSO_QUEUE;
1208 run_queue_hd = END_TSO_QUEUE;
1209 run_queue_tl = END_TSO_QUEUE;
1210 blocked_queue_hd = END_TSO_QUEUE;
1211 blocked_queue_tl = END_TSO_QUEUE;
1214 suspended_ccalling_threads = END_TSO_QUEUE;
1216 main_threads = NULL;
1221 enteredCAFs = END_CAF_LIST;
1223 /* Install the SIGHUP handler */
1226 struct sigaction action,oact;
1228 action.sa_handler = term_handler;
1229 sigemptyset(&action.sa_mask);
1230 action.sa_flags = 0;
1231 if (sigaction(SIGTERM, &action, &oact) != 0) {
1232 barf("can't install TERM handler");
1238 /* Allocate N Capabilities */
1241 Capability *cap, *prev;
1244 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1245 cap = stgMallocBytes(sizeof(Capability), "initScheduler:capabilities");
1249 free_capabilities = cap;
1250 n_free_capabilities = RtsFlags.ParFlags.nNodes;
1252 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: Allocated %d capabilities\n",
1253 n_free_capabilities););
1256 #if defined(SMP) || defined(PAR)
1269 /* make some space for saving all the thread ids */
1270 task_ids = stgMallocBytes(RtsFlags.ParFlags.nNodes * sizeof(task_info),
1271 "initScheduler:task_ids");
1273 /* and create all the threads */
1274 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1275 r = pthread_create(&tid,NULL,taskStart,NULL);
1277 barf("startTasks: Can't create new Posix thread");
1279 task_ids[i].id = tid;
1280 task_ids[i].mut_time = 0.0;
1281 task_ids[i].mut_etime = 0.0;
1282 task_ids[i].gc_time = 0.0;
1283 task_ids[i].gc_etime = 0.0;
1284 task_ids[i].elapsedtimestart = elapsedtime();
1285 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: Started task: %ld\n",tid););
1291 exitScheduler( void )
1296 /* Don't want to use pthread_cancel, since we'd have to install
1297 * these silly exception handlers (pthread_cleanup_{push,pop}) around
1301 /* Cancel all our tasks */
1302 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1303 pthread_cancel(task_ids[i].id);
1306 /* Wait for all the tasks to terminate */
1307 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1308 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: waiting for task %ld\n",
1310 pthread_join(task_ids[i].id, NULL);
1314 /* Send 'em all a SIGHUP. That should shut 'em up.
1316 await_death = RtsFlags.ParFlags.nNodes;
1317 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1318 pthread_kill(task_ids[i].id,SIGTERM);
1320 while (await_death > 0) {
1326 /* -----------------------------------------------------------------------------
1327 Managing the per-task allocation areas.
1329 Each capability comes with an allocation area. These are
1330 fixed-length block lists into which allocation can be done.
1332 ToDo: no support for two-space collection at the moment???
1333 -------------------------------------------------------------------------- */
1335 /* -----------------------------------------------------------------------------
1336 * waitThread is the external interface for running a new computataion
1337 * and waiting for the result.
1339 * In the non-SMP case, we create a new main thread, push it on the
1340 * main-thread stack, and invoke the scheduler to run it. The
1341 * scheduler will return when the top main thread on the stack has
1342 * completed or died, and fill in the necessary fields of the
1343 * main_thread structure.
1345 * In the SMP case, we create a main thread as before, but we then
1346 * create a new condition variable and sleep on it. When our new
1347 * main thread has completed, we'll be woken up and the status/result
1348 * will be in the main_thread struct.
1349 * -------------------------------------------------------------------------- */
1352 waitThread(StgTSO *tso, /*out*/StgClosure **ret)
1355 SchedulerStatus stat;
1357 ACQUIRE_LOCK(&sched_mutex);
1359 m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
1365 pthread_cond_init(&m->wakeup, NULL);
1368 m->link = main_threads;
1371 IF_DEBUG(scheduler, fprintf(stderr, "scheduler: new main thread (%d)\n",
1376 pthread_cond_wait(&m->wakeup, &sched_mutex);
1377 } while (m->stat == NoStatus);
1380 ASSERT(m->stat != NoStatus);
1386 pthread_cond_destroy(&m->wakeup);
1389 IF_DEBUG(scheduler, fprintf(stderr, "scheduler: main thread (%d) finished\n",
1393 RELEASE_LOCK(&sched_mutex);
1398 //@node Run queue code, Garbage Collextion Routines, Suspend and Resume, Main scheduling code
1399 //@subsection Run queue code
1403 NB: In GranSim we have many run queues; run_queue_hd is actually a macro
1404 unfolding to run_queue_hds[CurrentProc], thus CurrentProc is an
1405 implicit global variable that has to be correct when calling these
1409 /* Put the new thread on the head of the runnable queue.
1410 * The caller of createThread better push an appropriate closure
1411 * on this thread's stack before the scheduler is invoked.
1413 static /* inline */ void
1414 add_to_run_queue(tso)
1417 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
1418 tso->link = run_queue_hd;
1420 if (run_queue_tl == END_TSO_QUEUE) {
1425 /* Put the new thread at the end of the runnable queue. */
1426 static /* inline */ void
1427 push_on_run_queue(tso)
1430 ASSERT(get_itbl((StgClosure *)tso)->type == TSO);
1431 ASSERT(run_queue_hd!=NULL && run_queue_tl!=NULL);
1432 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
1433 if (run_queue_hd == END_TSO_QUEUE) {
1436 run_queue_tl->link = tso;
1442 Should be inlined because it's used very often in schedule. The tso
1443 argument is actually only needed in GranSim, where we want to have the
1444 possibility to schedule *any* TSO on the run queue, irrespective of the
1445 actual ordering. Therefore, if tso is not the nil TSO then we traverse
1446 the run queue and dequeue the tso, adjusting the links in the queue.
1448 //@cindex take_off_run_queue
1449 static /* inline */ StgTSO*
1450 take_off_run_queue(StgTSO *tso) {
1454 qetlaHbogh Qu' ngaSbogh ghomDaQ {tso} yIteq!
1456 if tso is specified, unlink that tso from the run_queue (doesn't have
1457 to be at the beginning of the queue); GranSim only
1459 if (tso!=END_TSO_QUEUE) {
1460 /* find tso in queue */
1461 for (t=run_queue_hd, prev=END_TSO_QUEUE;
1462 t!=END_TSO_QUEUE && t!=tso;
1466 /* now actually dequeue the tso */
1467 if (prev!=END_TSO_QUEUE) {
1468 ASSERT(run_queue_hd!=t);
1469 prev->link = t->link;
1471 /* t is at beginning of thread queue */
1472 ASSERT(run_queue_hd==t);
1473 run_queue_hd = t->link;
1475 /* t is at end of thread queue */
1476 if (t->link==END_TSO_QUEUE) {
1477 ASSERT(t==run_queue_tl);
1478 run_queue_tl = prev;
1480 ASSERT(run_queue_tl!=t);
1482 t->link = END_TSO_QUEUE;
1484 /* take tso from the beginning of the queue; std concurrent code */
1486 if (t != END_TSO_QUEUE) {
1487 run_queue_hd = t->link;
1488 t->link = END_TSO_QUEUE;
1489 if (run_queue_hd == END_TSO_QUEUE) {
1490 run_queue_tl = END_TSO_QUEUE;
1499 //@node Garbage Collextion Routines, Blocking Queue Routines, Run queue code, Main scheduling code
1500 //@subsection Garbage Collextion Routines
1502 /* ---------------------------------------------------------------------------
1503 Where are the roots that we know about?
1505 - all the threads on the runnable queue
1506 - all the threads on the blocked queue
1507 - all the thread currently executing a _ccall_GC
1508 - all the "main threads"
1510 ------------------------------------------------------------------------ */
1512 /* This has to be protected either by the scheduler monitor, or by the
1513 garbage collection monitor (probably the latter).
1517 static void GetRoots(void)
1524 for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
1525 if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
1526 run_queue_hds[i] = (StgTSO *)MarkRoot((StgClosure *)run_queue_hds[i]);
1527 if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
1528 run_queue_tls[i] = (StgTSO *)MarkRoot((StgClosure *)run_queue_tls[i]);
1530 if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
1531 blocked_queue_hds[i] = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_hds[i]);
1532 if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
1533 blocked_queue_tls[i] = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_tls[i]);
1534 if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
1535 ccalling_threadss[i] = (StgTSO *)MarkRoot((StgClosure *)ccalling_threadss[i]);
1542 run_queue_hd = (StgTSO *)MarkRoot((StgClosure *)run_queue_hd);
1543 run_queue_tl = (StgTSO *)MarkRoot((StgClosure *)run_queue_tl);
1545 blocked_queue_hd = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_hd);
1546 blocked_queue_tl = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_tl);
1549 for (m = main_threads; m != NULL; m = m->link) {
1550 m->tso = (StgTSO *)MarkRoot((StgClosure *)m->tso);
1552 suspended_ccalling_threads =
1553 (StgTSO *)MarkRoot((StgClosure *)suspended_ccalling_threads);
1555 #if defined(SMP) || defined(PAR) || defined(GRAN)
1560 /* -----------------------------------------------------------------------------
1563 This is the interface to the garbage collector from Haskell land.
1564 We provide this so that external C code can allocate and garbage
1565 collect when called from Haskell via _ccall_GC.
1567 It might be useful to provide an interface whereby the programmer
1568 can specify more roots (ToDo).
1570 This needs to be protected by the GC condition variable above. KH.
1571 -------------------------------------------------------------------------- */
1573 void (*extra_roots)(void);
1578 GarbageCollect(GetRoots);
1584 GetRoots(); /* the scheduler's roots */
1585 extra_roots(); /* the user's roots */
1589 performGCWithRoots(void (*get_roots)(void))
1591 extra_roots = get_roots;
1593 GarbageCollect(AllRoots);
1596 /* -----------------------------------------------------------------------------
1599 If the thread has reached its maximum stack size, then raise the
1600 StackOverflow exception in the offending thread. Otherwise
1601 relocate the TSO into a larger chunk of memory and adjust its stack
1603 -------------------------------------------------------------------------- */
1606 threadStackOverflow(StgTSO *tso)
1608 nat new_stack_size, new_tso_size, diff, stack_words;
1612 IF_DEBUG(sanity,checkTSO(tso));
1613 if (tso->stack_size >= tso->max_stack_size) {
1615 /* If we're debugging, just print out the top of the stack */
1616 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
1620 fprintf(stderr, "fatal: stack overflow in Hugs; aborting\n" );
1623 /* Send this thread the StackOverflow exception */
1624 raiseAsync(tso, (StgClosure *)&stackOverflow_closure);
1629 /* Try to double the current stack size. If that takes us over the
1630 * maximum stack size for this thread, then use the maximum instead.
1631 * Finally round up so the TSO ends up as a whole number of blocks.
1633 new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
1634 new_tso_size = (nat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
1635 TSO_STRUCT_SIZE)/sizeof(W_);
1636 new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
1637 new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
1639 IF_DEBUG(scheduler, fprintf(stderr,"scheduler: increasing stack size from %d words to %d.\n", tso->stack_size, new_stack_size));
1641 dest = (StgTSO *)allocate(new_tso_size);
1642 TICK_ALLOC_TSO(new_tso_size-sizeofW(StgTSO),0);
1644 /* copy the TSO block and the old stack into the new area */
1645 memcpy(dest,tso,TSO_STRUCT_SIZE);
1646 stack_words = tso->stack + tso->stack_size - tso->sp;
1647 new_sp = (P_)dest + new_tso_size - stack_words;
1648 memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
1650 /* relocate the stack pointers... */
1651 diff = (P_)new_sp - (P_)tso->sp; /* In *words* */
1652 dest->su = (StgUpdateFrame *) ((P_)dest->su + diff);
1654 dest->splim = (P_)dest->splim + (nat)((P_)dest - (P_)tso);
1655 dest->stack_size = new_stack_size;
1657 /* and relocate the update frame list */
1658 relocate_TSO(tso, dest);
1660 /* Mark the old TSO as relocated. We have to check for relocated
1661 * TSOs in the garbage collector and any primops that deal with TSOs.
1663 * It's important to set the sp and su values to just beyond the end
1664 * of the stack, so we don't attempt to scavenge any part of the
1667 tso->whatNext = ThreadRelocated;
1669 tso->sp = (P_)&(tso->stack[tso->stack_size]);
1670 tso->su = (StgUpdateFrame *)tso->sp;
1671 tso->why_blocked = NotBlocked;
1672 dest->mut_link = NULL;
1674 IF_DEBUG(sanity,checkTSO(tso));
1676 IF_DEBUG(scheduler,printTSO(dest));
1682 //@node Blocking Queue Routines, Exception Handling Routines, Garbage Collextion Routines, Main scheduling code
1683 //@subsection Blocking Queue Routines
1685 /* ---------------------------------------------------------------------------
1686 Wake up a queue that was blocked on some resource.
1687 ------------------------------------------------------------------------ */
1689 /* ToDo: check push_on_run_queue vs. PUSH_ON_RUN_QUEUE */
1693 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
1698 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
1700 /* write RESUME events to log file and
1701 update blocked and fetch time (depending on type of the orig closure) */
1702 if (RtsFlags.ParFlags.ParStats.Full) {
1703 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
1704 GR_RESUMEQ, ((StgTSO *)bqe), ((StgTSO *)bqe)->block_info.closure,
1705 0, 0 /* spark_queue_len(ADVISORY_POOL) */);
1707 switch (get_itbl(node)->type) {
1709 ((StgTSO *)bqe)->par.fetchtime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
1714 ((StgTSO *)bqe)->par.blocktime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
1717 barf("{unblockOneLocked}Daq Qagh: unexpected closure in blocking queue");
1724 static StgBlockingQueueElement *
1725 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
1727 StgBlockingQueueElement *next;
1728 PEs node_loc, tso_loc;
1730 node_loc = where_is(node); // should be lifted out of loop
1731 tso = (StgTSO *)bqe; // wastes an assignment to get the type right
1732 tso_loc = where_is(tso);
1733 if (IS_LOCAL_TO(PROCS(node),tso_loc)) { // TSO is local
1734 /* !fake_fetch => TSO is on CurrentProc is same as IS_LOCAL_TO */
1735 ASSERT(CurrentProc!=node_loc || tso_loc==CurrentProc);
1736 bq_processing_time += RtsFlags.GranFlags.Costs.lunblocktime;
1737 // insertThread(tso, node_loc);
1738 new_event(tso_loc, tso_loc,
1739 CurrentTime[CurrentProc]+bq_processing_time,
1741 tso, node, (rtsSpark*)NULL);
1742 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
1745 } else { // TSO is remote (actually should be FMBQ)
1746 bq_processing_time += RtsFlags.GranFlags.Costs.mpacktime;
1747 bq_processing_time += RtsFlags.GranFlags.Costs.gunblocktime;
1748 new_event(tso_loc, CurrentProc,
1749 CurrentTime[CurrentProc]+bq_processing_time+
1750 RtsFlags.GranFlags.Costs.latency,
1752 tso, node, (rtsSpark*)NULL);
1753 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
1754 bq_processing_time += RtsFlags.GranFlags.Costs.mtidytime;
1757 /* the thread-queue-overhead is accounted for in either Resume or UnblockThread */
1759 fprintf(stderr," %s TSO %d (%p) [PE %d] (blocked_on=%p) (next=%p) ,",
1760 (node_loc==tso_loc ? "Local" : "Global"),
1761 tso->id, tso, CurrentProc, tso->blocked_on, tso->link))
1762 tso->blocked_on = NULL;
1763 IF_DEBUG(scheduler,belch("-- Waking up thread %ld (%p)",
1767 /* if this is the BQ of an RBH, we have to put back the info ripped out of
1768 the closure to make room for the anchor of the BQ */
1769 if (next!=END_BQ_QUEUE) {
1770 ASSERT(get_itbl(node)->type == RBH && get_itbl(next)->type == CONSTR);
1772 ASSERT((info_ptr==&RBH_Save_0_info) ||
1773 (info_ptr==&RBH_Save_1_info) ||
1774 (info_ptr==&RBH_Save_2_info));
1776 /* cf. convertToRBH in RBH.c for writing the RBHSave closure */
1777 ((StgRBH *)node)->blocking_queue = ((StgRBHSave *)next)->payload[0];
1778 ((StgRBH *)node)->mut_link = ((StgRBHSave *)next)->payload[1];
1781 belch("## Filled in RBH_Save for %p (%s) at end of AwBQ",
1782 node, info_type(node)));
1786 static StgBlockingQueueElement *
1787 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
1789 StgBlockingQueueElement *next;
1791 switch (get_itbl(bqe)->type) {
1793 ASSERT(((StgTSO *)bqe)->why_blocked != NotBlocked);
1794 /* if it's a TSO just push it onto the run_queue */
1796 // ((StgTSO *)bqe)->link = END_TSO_QUEUE; // debugging?
1797 PUSH_ON_RUN_QUEUE((StgTSO *)bqe);
1799 unblockCount(bqe, node);
1800 /* reset blocking status after dumping event */
1801 ((StgTSO *)bqe)->why_blocked = NotBlocked;
1805 /* if it's a BLOCKED_FETCH put it on the PendingFetches list */
1807 bqe->link = PendingFetches;
1808 PendingFetches = bqe;
1812 /* can ignore this case in a non-debugging setup;
1813 see comments on RBHSave closures above */
1815 /* check that the closure is an RBHSave closure */
1816 ASSERT(get_itbl((StgClosure *)bqe) == &RBH_Save_0_info ||
1817 get_itbl((StgClosure *)bqe) == &RBH_Save_1_info ||
1818 get_itbl((StgClosure *)bqe) == &RBH_Save_2_info);
1822 barf("{unblockOneLocked}Daq Qagh: Unexpected IP (%#lx; %s) in blocking queue at %#lx\n",
1823 get_itbl((StgClosure *)bqe), info_type((StgClosure *)bqe),
1827 // IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
1831 #else /* !GRAN && !PAR */
1833 unblockOneLocked(StgTSO *tso)
1837 ASSERT(get_itbl(tso)->type == TSO);
1838 ASSERT(tso->why_blocked != NotBlocked);
1839 tso->why_blocked = NotBlocked;
1841 PUSH_ON_RUN_QUEUE(tso);
1843 IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
1848 #if defined(PAR) || defined(GRAN)
1850 unblockOne(StgTSO *tso, StgClosure *node)
1852 ACQUIRE_LOCK(&sched_mutex);
1853 tso = unblockOneLocked(tso, node);
1854 RELEASE_LOCK(&sched_mutex);
1859 unblockOne(StgTSO *tso)
1861 ACQUIRE_LOCK(&sched_mutex);
1862 tso = unblockOneLocked(tso);
1863 RELEASE_LOCK(&sched_mutex);
1870 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
1872 StgBlockingQueueElement *bqe, *next;
1874 PEs node_loc, tso_loc;
1875 rtsTime bq_processing_time = 0;
1876 nat len = 0, len_local = 0;
1879 belch("## AwBQ for node %p on PE %d @ %ld by TSO %d (%p): ", \
1880 node, CurrentProc, CurrentTime[CurrentProc],
1881 CurrentTSO->id, CurrentTSO));
1883 node_loc = where_is(node);
1885 ASSERT(get_itbl(q)->type == TSO || // q is either a TSO or an RBHSave
1886 get_itbl(q)->type == CONSTR); // closure (type constructor)
1887 ASSERT(is_unique(node));
1889 /* FAKE FETCH: magically copy the node to the tso's proc;
1890 no Fetch necessary because in reality the node should not have been
1891 moved to the other PE in the first place
1893 if (CurrentProc!=node_loc) {
1895 belch("## node %p is on PE %d but CurrentProc is %d (TSO %d); assuming fake fetch and adjusting bitmask (old: %#x)",
1896 node, node_loc, CurrentProc, CurrentTSO->id,
1897 // CurrentTSO, where_is(CurrentTSO),
1898 node->header.gran.procs));
1899 node->header.gran.procs = (node->header.gran.procs) | PE_NUMBER(CurrentProc);
1901 belch("## new bitmask of node %p is %#x",
1902 node, node->header.gran.procs));
1903 if (RtsFlags.GranFlags.GranSimStats.Global) {
1904 globalGranStats.tot_fake_fetches++;
1909 // ToDo: check: ASSERT(CurrentProc==node_loc);
1910 while (get_itbl(bqe)->type==TSO) { // q != END_TSO_QUEUE) {
1913 bqe points to the current element in the queue
1914 next points to the next element in the queue
1916 //tso = (StgTSO *)bqe; // wastes an assignment to get the type right
1917 //tso_loc = where_is(tso);
1918 bqe = unblockOneLocked(bqe, node);
1921 /* statistics gathering */
1922 /* ToDo: fix counters
1923 if (RtsFlags.GranFlags.GranSimStats.Global) {
1924 globalGranStats.tot_bq_processing_time += bq_processing_time;
1925 globalGranStats.tot_bq_len += len; // total length of all bqs awakened
1926 globalGranStats.tot_bq_len_local += len_local; // same for local TSOs only
1927 globalGranStats.tot_awbq++; // total no. of bqs awakened
1930 fprintf(stderr,"## BQ Stats of %p: [%d entries, %d local] %s\n",
1931 node, len, len_local, (next!=END_TSO_QUEUE) ? "RBH" : ""));
1936 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
1938 StgBlockingQueueElement *bqe, *next;
1940 ACQUIRE_LOCK(&sched_mutex);
1942 IF_PAR_DEBUG(verbose,
1943 belch("## AwBQ for node %p on [%x]: ",
1946 ASSERT(get_itbl(q)->type == TSO ||
1947 get_itbl(q)->type == BLOCKED_FETCH ||
1948 get_itbl(q)->type == CONSTR);
1951 while (get_itbl(bqe)->type==TSO ||
1952 get_itbl(bqe)->type==BLOCKED_FETCH) {
1953 bqe = unblockOneLocked(bqe, node);
1955 RELEASE_LOCK(&sched_mutex);
1958 #else /* !GRAN && !PAR */
1960 awakenBlockedQueue(StgTSO *tso)
1962 ACQUIRE_LOCK(&sched_mutex);
1963 while (tso != END_TSO_QUEUE) {
1964 tso = unblockOneLocked(tso);
1966 RELEASE_LOCK(&sched_mutex);
1970 //@node Exception Handling Routines, Debugging Routines, Blocking Queue Routines, Main scheduling code
1971 //@subsection Exception Handling Routines
1973 /* ---------------------------------------------------------------------------
1975 - usually called inside a signal handler so it mustn't do anything fancy.
1976 ------------------------------------------------------------------------ */
1979 interruptStgRts(void)
1985 /* -----------------------------------------------------------------------------
1988 This is for use when we raise an exception in another thread, which
1990 This has nothing to do with the UnblockThread event in GranSim. -- HWL
1991 -------------------------------------------------------------------------- */
1994 unblockThread(StgTSO *tso)
1998 ACQUIRE_LOCK(&sched_mutex);
1999 switch (tso->why_blocked) {
2002 return; /* not blocked */
2005 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
2007 StgTSO *last_tso = END_TSO_QUEUE;
2008 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
2011 for (t = mvar->head; t != END_TSO_QUEUE;
2012 last = &t->link, last_tso = t, t = t->link) {
2015 if (mvar->tail == tso) {
2016 mvar->tail = last_tso;
2021 barf("unblockThread (MVAR): TSO not found");
2024 case BlockedOnBlackHole:
2025 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
2027 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
2029 last = &bq->blocking_queue;
2030 for (t = bq->blocking_queue; t != END_TSO_QUEUE;
2031 last = &t->link, t = t->link) {
2037 barf("unblockThread (BLACKHOLE): TSO not found");
2040 case BlockedOnException:
2042 StgTSO *target = tso->block_info.tso;
2044 ASSERT(get_itbl(target)->type == TSO);
2045 ASSERT(target->blocked_exceptions != NULL);
2047 last = &target->blocked_exceptions;
2048 for (t = target->blocked_exceptions; t != END_TSO_QUEUE;
2049 last = &t->link, t = t->link) {
2050 ASSERT(get_itbl(t)->type == TSO);
2056 barf("unblockThread (Exception): TSO not found");
2059 case BlockedOnDelay:
2061 case BlockedOnWrite:
2063 StgTSO *prev = NULL;
2064 for (t = blocked_queue_hd; t != END_TSO_QUEUE;
2065 prev = t, t = t->link) {
2068 blocked_queue_hd = t->link;
2069 if (blocked_queue_tl == t) {
2070 blocked_queue_tl = END_TSO_QUEUE;
2073 prev->link = t->link;
2074 if (blocked_queue_tl == t) {
2075 blocked_queue_tl = prev;
2081 barf("unblockThread (I/O): TSO not found");
2085 barf("unblockThread");
2089 tso->link = END_TSO_QUEUE;
2090 tso->why_blocked = NotBlocked;
2091 tso->block_info.closure = NULL;
2092 PUSH_ON_RUN_QUEUE(tso);
2093 RELEASE_LOCK(&sched_mutex);
2096 /* -----------------------------------------------------------------------------
2099 * The following function implements the magic for raising an
2100 * asynchronous exception in an existing thread.
2102 * We first remove the thread from any queue on which it might be
2103 * blocked. The possible blockages are MVARs and BLACKHOLE_BQs.
2105 * We strip the stack down to the innermost CATCH_FRAME, building
2106 * thunks in the heap for all the active computations, so they can
2107 * be restarted if necessary. When we reach a CATCH_FRAME, we build
2108 * an application of the handler to the exception, and push it on
2109 * the top of the stack.
2111 * How exactly do we save all the active computations? We create an
2112 * AP_UPD for every UpdateFrame on the stack. Entering one of these
2113 * AP_UPDs pushes everything from the corresponding update frame
2114 * upwards onto the stack. (Actually, it pushes everything up to the
2115 * next update frame plus a pointer to the next AP_UPD object.
2116 * Entering the next AP_UPD object pushes more onto the stack until we
2117 * reach the last AP_UPD object - at which point the stack should look
2118 * exactly as it did when we killed the TSO and we can continue
2119 * execution by entering the closure on top of the stack.
2121 * We can also kill a thread entirely - this happens if either (a) the
2122 * exception passed to raiseAsync is NULL, or (b) there's no
2123 * CATCH_FRAME on the stack. In either case, we strip the entire
2124 * stack and replace the thread with a zombie.
2126 * -------------------------------------------------------------------------- */
2129 deleteThread(StgTSO *tso)
2131 raiseAsync(tso,NULL);
2135 raiseAsync(StgTSO *tso, StgClosure *exception)
2137 StgUpdateFrame* su = tso->su;
2138 StgPtr sp = tso->sp;
2140 /* Thread already dead? */
2141 if (tso->whatNext == ThreadComplete || tso->whatNext == ThreadKilled) {
2145 IF_DEBUG(scheduler, sched_belch("raising exception in thread %ld.", tso->id));
2147 /* Remove it from any blocking queues */
2150 /* The stack freezing code assumes there's a closure pointer on
2151 * the top of the stack. This isn't always the case with compiled
2152 * code, so we have to push a dummy closure on the top which just
2153 * returns to the next return address on the stack.
2155 if ( LOOKS_LIKE_GHC_INFO((void*)*sp) ) {
2156 *(--sp) = (W_)&dummy_ret_closure;
2160 int words = ((P_)su - (P_)sp) - 1;
2164 /* If we find a CATCH_FRAME, and we've got an exception to raise,
2165 * then build PAP(handler,exception,realworld#), and leave it on
2166 * top of the stack ready to enter.
2168 if (get_itbl(su)->type == CATCH_FRAME && exception != NULL) {
2169 StgCatchFrame *cf = (StgCatchFrame *)su;
2170 /* we've got an exception to raise, so let's pass it to the
2171 * handler in this frame.
2173 ap = (StgAP_UPD *)allocate(sizeofW(StgPAP) + 2);
2174 TICK_ALLOC_UPD_PAP(3,0);
2175 SET_HDR(ap,&PAP_info,cf->header.prof.ccs);
2178 ap->fun = cf->handler; /* :: Exception -> IO a */
2179 ap->payload[0] = (P_)exception;
2180 ap->payload[1] = ARG_TAG(0); /* realworld token */
2182 /* throw away the stack from Sp up to and including the
2185 sp = (P_)su + sizeofW(StgCatchFrame) - 1;
2188 /* Restore the blocked/unblocked state for asynchronous exceptions
2189 * at the CATCH_FRAME.
2191 * If exceptions were unblocked at the catch, arrange that they
2192 * are unblocked again after executing the handler by pushing an
2193 * unblockAsyncExceptions_ret stack frame.
2195 if (!cf->exceptions_blocked) {
2196 *(sp--) = (W_)&unblockAsyncExceptionszh_ret_info;
2199 /* Ensure that async exceptions are blocked when running the handler.
2201 if (tso->blocked_exceptions == NULL) {
2202 tso->blocked_exceptions = END_TSO_QUEUE;
2205 /* Put the newly-built PAP on top of the stack, ready to execute
2206 * when the thread restarts.
2210 tso->whatNext = ThreadEnterGHC;
2214 /* First build an AP_UPD consisting of the stack chunk above the
2215 * current update frame, with the top word on the stack as the
2218 ap = (StgAP_UPD *)allocate(AP_sizeW(words));
2223 ap->fun = (StgClosure *)sp[0];
2225 for(i=0; i < (nat)words; ++i) {
2226 ap->payload[i] = (P_)*sp++;
2229 switch (get_itbl(su)->type) {
2233 SET_HDR(ap,&AP_UPD_info,su->header.prof.ccs /* ToDo */);
2234 TICK_ALLOC_UP_THK(words+1,0);
2237 fprintf(stderr, "scheduler: Updating ");
2238 printPtr((P_)su->updatee);
2239 fprintf(stderr, " with ");
2240 printObj((StgClosure *)ap);
2243 /* Replace the updatee with an indirection - happily
2244 * this will also wake up any threads currently
2245 * waiting on the result.
2247 UPD_IND_NOLOCK(su->updatee,ap); /* revert the black hole */
2249 sp += sizeofW(StgUpdateFrame) -1;
2250 sp[0] = (W_)ap; /* push onto stack */
2256 StgCatchFrame *cf = (StgCatchFrame *)su;
2259 /* We want a PAP, not an AP_UPD. Fortunately, the
2260 * layout's the same.
2262 SET_HDR(ap,&PAP_info,su->header.prof.ccs /* ToDo */);
2263 TICK_ALLOC_UPD_PAP(words+1,0);
2265 /* now build o = FUN(catch,ap,handler) */
2266 o = (StgClosure *)allocate(sizeofW(StgClosure)+2);
2267 TICK_ALLOC_FUN(2,0);
2268 SET_HDR(o,&catch_info,su->header.prof.ccs /* ToDo */);
2269 o->payload[0] = (StgClosure *)ap;
2270 o->payload[1] = cf->handler;
2273 fprintf(stderr, "scheduler: Built ");
2274 printObj((StgClosure *)o);
2277 /* pop the old handler and put o on the stack */
2279 sp += sizeofW(StgCatchFrame) - 1;
2286 StgSeqFrame *sf = (StgSeqFrame *)su;
2289 SET_HDR(ap,&PAP_info,su->header.prof.ccs /* ToDo */);
2290 TICK_ALLOC_UPD_PAP(words+1,0);
2292 /* now build o = FUN(seq,ap) */
2293 o = (StgClosure *)allocate(sizeofW(StgClosure)+1);
2294 TICK_ALLOC_SE_THK(1,0);
2295 SET_HDR(o,&seq_info,su->header.prof.ccs /* ToDo */);
2296 payloadCPtr(o,0) = (StgClosure *)ap;
2299 fprintf(stderr, "scheduler: Built ");
2300 printObj((StgClosure *)o);
2303 /* pop the old handler and put o on the stack */
2305 sp += sizeofW(StgSeqFrame) - 1;
2311 /* We've stripped the entire stack, the thread is now dead. */
2312 sp += sizeofW(StgStopFrame) - 1;
2313 sp[0] = (W_)exception; /* save the exception */
2314 tso->whatNext = ThreadKilled;
2315 tso->su = (StgUpdateFrame *)(sp+1);
2326 //@node Debugging Routines, Index, Exception Handling Routines, Main scheduling code
2327 //@subsection Debugging Routines
2329 /* -----------------------------------------------------------------------------
2330 Debugging: why is a thread blocked
2331 -------------------------------------------------------------------------- */
2335 void printThreadBlockage(StgTSO *tso)
2337 switch (tso->why_blocked) {
2339 fprintf(stderr,"blocked on read from fd %d", tso->block_info.fd);
2341 case BlockedOnWrite:
2342 fprintf(stderr,"blocked on write to fd %d", tso->block_info.fd);
2344 case BlockedOnDelay:
2345 fprintf(stderr,"blocked on delay of %d ms", tso->block_info.delay);
2348 fprintf(stderr,"blocked on an MVar");
2350 case BlockedOnException:
2351 fprintf(stderr,"blocked on delivering an exception to thread %d",
2352 tso->block_info.tso->id);
2354 case BlockedOnBlackHole:
2355 fprintf(stderr,"blocked on a black hole");
2358 fprintf(stderr,"not blocked");
2362 fprintf(stderr,"blocked on global address");
2369 Print a whole blocking queue attached to node (debugging only).
2374 print_bq (StgClosure *node)
2376 StgBlockingQueueElement *bqe;
2380 fprintf(stderr,"## BQ of closure %p (%s): ",
2381 node, info_type(node));
2383 /* should cover all closures that may have a blocking queue */
2384 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
2385 get_itbl(node)->type == FETCH_ME_BQ ||
2386 get_itbl(node)->type == RBH);
2388 ASSERT(node!=(StgClosure*)NULL); // sanity check
2390 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
2392 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
2393 !end; // iterate until bqe points to a CONSTR
2394 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
2395 ASSERT(bqe != END_BQ_QUEUE); // sanity check
2396 ASSERT(bqe != (StgTSO*)NULL); // sanity check
2397 /* types of closures that may appear in a blocking queue */
2398 ASSERT(get_itbl(bqe)->type == TSO ||
2399 get_itbl(bqe)->type == BLOCKED_FETCH ||
2400 get_itbl(bqe)->type == CONSTR);
2401 /* only BQs of an RBH end with an RBH_Save closure */
2402 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
2404 switch (get_itbl(bqe)->type) {
2406 fprintf(stderr," TSO %d (%x),",
2407 ((StgTSO *)bqe)->id, ((StgTSO *)bqe));
2410 fprintf(stderr," BF (node=%p, ga=((%x, %d, %x)),",
2411 ((StgBlockedFetch *)bqe)->node,
2412 ((StgBlockedFetch *)bqe)->ga.payload.gc.gtid,
2413 ((StgBlockedFetch *)bqe)->ga.payload.gc.slot,
2414 ((StgBlockedFetch *)bqe)->ga.weight);
2417 fprintf(stderr," %s (IP %p),",
2418 (get_itbl(bqe) == &RBH_Save_0_info ? "RBH_Save_0" :
2419 get_itbl(bqe) == &RBH_Save_1_info ? "RBH_Save_1" :
2420 get_itbl(bqe) == &RBH_Save_2_info ? "RBH_Save_2" :
2421 "RBH_Save_?"), get_itbl(bqe));
2424 barf("Unexpected closure type %s in blocking queue of %p (%s)",
2425 info_type(bqe), node, info_type(node));
2429 fputc('\n', stderr);
2431 # elif defined(GRAN)
2433 print_bq (StgClosure *node)
2435 StgBlockingQueueElement *bqe;
2437 PEs node_loc, tso_loc;
2440 /* should cover all closures that may have a blocking queue */
2441 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
2442 get_itbl(node)->type == FETCH_ME_BQ ||
2443 get_itbl(node)->type == RBH);
2445 ASSERT(node!=(StgClosure*)NULL); // sanity check
2446 node_loc = where_is(node);
2448 fprintf(stderr,"## BQ of closure %p (%s) on [PE %d]: ",
2449 node, info_type(node), node_loc);
2452 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
2454 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
2455 !end; // iterate until bqe points to a CONSTR
2456 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
2457 ASSERT(bqe != END_BQ_QUEUE); // sanity check
2458 ASSERT(bqe != (StgTSO*)NULL); // sanity check
2459 /* types of closures that may appear in a blocking queue */
2460 ASSERT(get_itbl(bqe)->type == TSO ||
2461 get_itbl(bqe)->type == CONSTR);
2462 /* only BQs of an RBH end with an RBH_Save closure */
2463 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
2465 tso_loc = where_is((StgClosure *)bqe);
2466 switch (get_itbl(bqe)->type) {
2468 fprintf(stderr," TSO %d (%x) on [PE %d],",
2469 ((StgTSO *)bqe)->id, ((StgTSO *)bqe), tso_loc);
2472 fprintf(stderr," %s (IP %p),",
2473 (get_itbl(bqe) == &RBH_Save_0_info ? "RBH_Save_0" :
2474 get_itbl(bqe) == &RBH_Save_1_info ? "RBH_Save_1" :
2475 get_itbl(bqe) == &RBH_Save_2_info ? "RBH_Save_2" :
2476 "RBH_Save_?"), get_itbl(bqe));
2479 barf("Unexpected closure type %s in blocking queue of %p (%s)",
2480 info_type(bqe), node, info_type(node));
2484 fputc('\n', stderr);
2488 Nice and easy: only TSOs on the blocking queue
2491 print_bq (StgClosure *node)
2495 ASSERT(node!=(StgClosure*)NULL); // sanity check
2496 for (tso = ((StgBlockingQueue*)node)->blocking_queue;
2497 tso != END_TSO_QUEUE;
2499 ASSERT(tso!=NULL && tso!=END_TSO_QUEUE); // sanity check
2500 ASSERT(get_itbl(tso)->type == TSO); // guess what, sanity check
2501 fprintf(stderr," TSO %d (%p),", tso->id, tso);
2503 fputc('\n', stderr);
2514 for (i=0, tso=run_queue_hd;
2515 tso != END_TSO_QUEUE;
2524 sched_belch(char *s, ...)
2529 fprintf(stderr, "scheduler (task %ld): ", pthread_self());
2531 fprintf(stderr, "scheduler: ");
2533 vfprintf(stderr, s, ap);
2534 fprintf(stderr, "\n");
2539 //@node Index, , Debugging Routines, Main scheduling code
2543 //* MainRegTable:: @cindex\s-+MainRegTable
2544 //* StgMainThread:: @cindex\s-+StgMainThread
2545 //* awaken_blocked_queue:: @cindex\s-+awaken_blocked_queue
2546 //* blocked_queue_hd:: @cindex\s-+blocked_queue_hd
2547 //* blocked_queue_tl:: @cindex\s-+blocked_queue_tl
2548 //* context_switch:: @cindex\s-+context_switch
2549 //* createThread:: @cindex\s-+createThread
2550 //* free_capabilities:: @cindex\s-+free_capabilities
2551 //* gc_pending_cond:: @cindex\s-+gc_pending_cond
2552 //* initScheduler:: @cindex\s-+initScheduler
2553 //* interrupted:: @cindex\s-+interrupted
2554 //* n_free_capabilities:: @cindex\s-+n_free_capabilities
2555 //* next_thread_id:: @cindex\s-+next_thread_id
2556 //* print_bq:: @cindex\s-+print_bq
2557 //* run_queue_hd:: @cindex\s-+run_queue_hd
2558 //* run_queue_tl:: @cindex\s-+run_queue_tl
2559 //* sched_mutex:: @cindex\s-+sched_mutex
2560 //* schedule:: @cindex\s-+schedule
2561 //* take_off_run_queue:: @cindex\s-+take_off_run_queue
2562 //* task_ids:: @cindex\s-+task_ids
2563 //* term_mutex:: @cindex\s-+term_mutex
2564 //* thread_ready_cond:: @cindex\s-+thread_ready_cond